1. Field
The following description relates to a sensor communication service, and more particularly, to a packet relay apparatus and method for a sensor communication.
2. Description of Related Art
A sensor network is a type of wireless network that transmits sensing information generated by a sensor to the final transmission via wireless communications. The sensor network is based on a lower data transfer rate compared to a mobile telecommunication network, and supplying it with power by cables is difficult; as such, the sensor network generally operates on battery.
The IEEE802.15.4 is the archetypal international standard for wireless sensor communications and network configuration. According to the IEEE802.15.4, a total of 16 5-MHz channels are each operated at a 2.4 GHz band. One personal area network (PAN) can be formed in each channel, and serve as a basic unit of a sensor network. A PAN coordinator manages one PAN, and multiple devices or coordinators may be connected to the PAN coordinator.
The PAN coordinator transmits a beacon at regular time intervals, and one time interval between beacons forms one wireless frame. One wireless frame is composed of an active period during which data transmission/reception is enabled, and an inactive period during which data transmission/reception is disabled.